An apparatus is known for working a garbage heap. This apparatus comprises a self-propelled portal frame having a pair of side portions spaced apart transverse to the normal direction of travel of the device. A turning roller or cylinder extending transverse to this direction is suspended on the frame between the side portions. The side portions ride on rails set into the ground. This device is driven along on elongated heap of garbage or the like and serves to turn it. See German published specification No. 1,905,005.
Such an arrangement is completely unsuitable for use in turning a silo. Mainly the device is extremely expensive so that its periodic use, as a silo need only be turned from time to time, cannot justify the considerable expense. Even in very big operations such a device is economically unjustifiable.